TY - JOUR
A1 - Evsevleev, Sergei
A1 - Müller, Bernd R.
A1 - Lange, Axel
A1 - Kupsch, Andreas
T1 - Refraction driven X-ray caustics at curved interfaces
N2 - X-ray refraction related interaction has received rising interest since about two decades in the field of imaging, beam shaping and analysis although being discovered a century ago. Due to refraction at interfaces in inhomogeneous media X-rays undergo natural focusing (or defocusing) of waves, revealing caustics. Such Kind of intensity patterns are well-known for visible light, but have been sparsely discussed for X-rays. The Variation of irradiation density may be predicted in case of known shapes. Analogously to light optics, the intensity distributions cover several orders of magnitude including complete extinction. The partly convergent (and divergent) caustic stripes originate from narrow zones of typical size of some 10−6 of the boundary curvature radius. For the deflection of plane wave synchrotron radiation (energy in the range of some keV to some ten keV) at rods and tubes of several μm diameter, we find good Agreement between experiments and modeling by ray tracing according to Snell’s law without additional diffraction contributions. Apart from Basic Research implications, caustics may influence the performance of irradiation technologies such as sterilization or molecular cross-linking.
KW - X-ray caustics
KW - X-ray refraction
KW - Irradiation
KW - Radiation shielding
KW - Synchrotron Radiation
PY - 2019
UR - http://www.sciencedirect.com/science/article/pii/S0168900218314591
DO - https://doi.org/10.1016/j.nima.2018.10.152
SN - 0168-9002
SN - 1872-9576
VL - 916
SP - 275
EP - 282
PB - Elsevier
AN - OPUS4-46924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Laquai, René
A1 - Schaupp, Thomas
A1 - Müller, Bernd R.
A1 - Griesche, Axel
A1 - Bruno, Giovanni
A1 - Kannengießer, Thomas
T1 - 3D imaging of hydrogen assisted cracking in metals using refraction enhanced synchrotron CT
N2 - Hydrogen in metals can cause a degradation of the mechanical properties with possible subsequent hydrogen assisted cracking (HAC). Though, the mechanism of HAC is not completely understood yet and thus suitable methods for in situ investigations to characterise the crack formation are needed. X-ray computed tomography (CT) is a well-known tool for analysing these properties. However, the effective resolution of the detector system limits the detection of small defects by CT. Analyser based imaging (ABI) takes advantage of x-ray refraction at interfaces between volumes of different density, i.e. of cracks, pores, inclusions, etc., within the sample to detect defects smaller than the resolution of the detector system. In this study, measurements on an aluminium alloy weld showed that ABI allows us to resolve the 3D structure of cracks undetected by absorption based CT. Prospective investigations will analyse HAC in steels.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 2015-09-15
KW - Wasserstoffversprödung
KW - Wasserstoffunterstützte Rissbildung
KW - Röntgenrefraktion
KW - CT
KW - Hydrogen embrittlement (HE)
KW - Hydrogen assisted cracking (HAC)
KW - Aluminium alloy
KW - X-ray refraction
KW - Analyser based imaging
KW - Computed tomography (CT)
KW - Synchrotron radiation
PY - 2015
SN - 1435-4934
SP - 1217
EP - 1224
AN - OPUS4-34287
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shashev, Yury
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Improving the visibility of phase gratings for Talbot-Lau X-ray imaging
N2 - Talbot-Lau interferometry provides X-ray imaging techniques with significant enhancement of the radiographic contrast of weakly absorbing objects. The grating based technique allows separation of absorption, refraction and small angle scattering effects. The different efficiency of rectangular and triangular shaped phase gratings at varying detector distances is investigated. The interference patterns (Talbot carpets) are modeled for parallel monochromatic radiation and measured by synchrotron radiation. In comparison to rectangular shapes of phase gratings much higher visibility is obtained for triangular shapes which yield enhanced contrast of a glass capillary test specimen.
KW - Visibility
KW - Talbot-Lau interferometry
KW - Phase grating
KW - Synchrotron imaging
KW - X-ray reefraction
PY - 2016
DO - https://doi.org/10.3139/120.110948
SN - 0025-5300
VL - 58
IS - 11-12
SP - 970
EP - 974
PB - Carl Hanser Verlag
CY - München
AN - OPUS4-38422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Laquai, René
A1 - Schaupp, Thomas
A1 - Müller, Bernd R.
A1 - Griesche, Axel
A1 - Bruno, Giovanni
A1 - Kannengießer, Thomas
T1 - 3D imaging of hydrogen assisted cracking using analyser-based imaging
N2 - To better understand the mechanism of hydrogen assisted cracking (HAC), it is important to investigate the 3D structure of the cracks non-destructively. Since, cracks introduced by HAC are usually very small, conventional x-ray imaging methods often lack the required spatial resolution.
However, the detection of those cracks can be enhanced by taking advantage of refraction at interfaces within the sample.
To image this refractive deflection we employ analyser based imaging (ABI). In this work we aim at proving the enhanced crack detection of ABI by investigating an alluminum alloy weld.
T2 - BESSY User Meeting 2015
CY - Berlin, Germany
DA - 09.12.2015
KW - X-ray refraction
KW - Synchrotron
KW - Analyser-based imaging
KW - Hydrogen assisted cracking
KW - Welding
PY - 2015
AN - OPUS4-38278
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shashev, Yury
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Evsevleev, Sergei
A1 - Müller, Bernd R.
A1 - Osenberg, Markus
A1 - Manke, Ingo
A1 - Hentschel, Manfred P.
A1 - Bruno, Giovanni
T1 - Optimizing the visibility of X-ray phase grating interferometry
N2 - The performance of grating interferometers coming up now for Imaging interfaces within materials depends on the efficiency (visibility) of their main component, namely the phase grating. Therefore, experiments with monochromatic synchrotron radiation and corresponding simulations are carried out. The visibility of a Phase grating is optimized by different photon energies, varying detector to grating distances and continuous rotation of the phase grating about the grid lines. Such kind of rotation changes the projected grating shapes, and thereby the distribution profiles of phase shifts. This yields higher visibilities than derived from ideal rectangular shapes. By continuous grating rotation and variation of the propagation distance, we achieve 2D visibility maps. Such maps provide the visibility for a certain combination of grating orientation and detector position. Optimum visibilities occur at considerably smaller distances than in the standard setup.
KW - Synchrotron, BAMline
KW - Talbot-Lau interferometer
KW - X-ray imaging
KW - X-ray refraction
KW - Grating interferometry
KW - X-ray phase contrast
PY - 2017
DO - https://doi.org/10.3139/120.111097
SN - 0025-5300
VL - 59
IS - 11-12
SP - 974
EP - 980
PB - Hanser Verlag
AN - OPUS4-42955
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Onel, Yener
A1 - Wolk, Thomas
A1 - Staude, Andreas
A1 - Ehrig, Karsten
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Evaluating porosity in cordierite diesel particulate filter materials: advanced X-ray techniques and new statistical analysis methods
N2 - Bi-continuous porous ceramics for filtration applications possess a particularly complicated microstructure, whereby porosity and solid matter are intermingled. Mechanical, thermal, and filtration properties can only be precisely estimated if the morphology of both solid matter and porosity can be quantitatively determined. Using 3D computed tomography (CT) at different resolutions, and several X-ray refraction-based techniques, we quantitatively evaluated porosity and pore orientation in cordierite diesel particulate filter ceramics.Moreover, applying both Fast Fourier Transform (FFT) and a newly developed image analysis algorithm (directional interface variance analysis, DIVA), we quantitatively evaluated porosity and pore orientation. Both the experimental techniques and the statistical approach allow extraction of spatially resolved or average values.Porosity values from synchrotron computed tomography used turn out to agree with mercury intrusion measurements, while pore orientation factors agree with published crystallographic texture data. This latter point also implies that the study of the pore/matter interface is sufficient to describe the morphological properties of these materials.
KW - Diesel particulate filters
KW - DIVA Algorithm
KW - Pore Orientation
KW - Porous Ceramics
KW - X-Ray Computed Tomography
KW - X-Ray Refraction
PY - 2014
DO - https://doi.org/10.4028/www.scientific.net/AST.91.64
SN - 1662-0356
VL - 91
SP - 64
EP - 69
PB - Techna
CY - Faenza
AN - OPUS4-32069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Lange, Axel
A1 - Bruno, Giovanni
T1 - Microstructure Characterization of Ceramics via 2D and 3D X-Ray Refraction Techniques
N2 - 3D imaging techniques are very fashionable nowadays, and allow enormous progress in understanding ceramic microstructure, its evolution, and its link to mechanical, thermal, and transport properties. In this feature article, we report the use of a powerful, yet not so wide-spread, set of X-ray techniques based on refraction effects. X-ray refraction allows determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with a nanometric detectability. While the techniques are limited by the X-ray absorption of the material under investigation, we demonstrate showcases of ceramics and composite materials, where understanding of process parameter influence or simply of microstructural parameters could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography.
KW - X-ray refraction
KW - Porosity
KW - Specific surface
KW - Crack detection
KW - Composites
PY - 2017
DO - https://doi.org/10.1016/j.jeurceramsoc.2016.12.031
SN - 0955-2219
SN - 1873-619X
VL - 37
IS - 5
SP - 1879
EP - 1889
PB - Elsevier
CY - Amsterdam
AN - OPUS4-39094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
T1 - Correction of diffuse X-ray detector based background
N2 - A novel approach to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background Signals (backlight) of 2D X-ray detectors is suggested. Depending on the detector geometry the mechanism may be different, either based on the optical scattering of the fluorescent screen materials into optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert Beers law in single projections (radiographs).
When used as input data for computed tomography these violations are directly observed via modulation of the projected mass as a function of the rotation Phase and the samples aspect ratio (dynamics). The magnitude of the diffuse Background signal depends on the detector area covered by the projected sample. They are more pronounced the smaller the shaded area and the stronger the total attenuation.
Moreover, the local intensity mismatch depends on the attenuation of the sample.
We present very basic reference data measured with multiple metal foils at a synchrotron radiation source. Beam hardening artifacts can be excluded due to the monochromatic radiation. The proposed correction procedure assumes a constant (non-local) scattering mechanism.
T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography
CY - Berlin, Germany
DA - 20.06.2011
KW - Backlight
KW - X-ray detector
KW - Fluorescence screen
KW - Synchrotron radiography
KW - Computed tomography
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243589
SN - 978-3-940283-34-4
IS - DGZfP-BB 128 (Poster 24)
SP - 1
EP - 7
PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Hentschel, Manfred P.
A1 - Lange, Axel
A1 - Müller, Bernd R.
T1 - Röntgen-Interface-Radiographie im Dunkelfeld
N2 - Es wird ein Verfahren zur Röntgenabbildung schwach absorbierender Objekte vorgestellt. Als kontrastgebender Effekt wird die Röntgenrefraktion an Ober- und Grenzflächen ausgenutzt. Zur Erzeugung eines sogenannten Dunkelfeldes wird ein schwach gekrümmter Transmissionskristall eingesetzt, der lokal, d.h. in einem kleinen Ausschnitt des Einstrahlquerschnitts, die Bragg-Bedingung erfüllt. Innerhalb dieser Zone erscheinen die durch Refraktion abgelenkten Strahlkomponenten als hell leuchtende Interface-Strukturen. Die Synthese mehrerer Dunkelfeldstreifen ergibt hochaufgelöste 2D Beispiel von biologischen und technischen Mikrostrukturen.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Refraction enhanced imaging (REI)
KW - Radiographie
KW - Dunkelfeldabbildung
KW - Röntgenrefraktion
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-286900
SN - 978-3-940283-49-8
IS - Di.3.C.1
SP - 1
EP - 7
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28690
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Axel
A1 - Altmann, Korinna
A1 - Kocher, B.
A1 - Braun, U.
T1 - Determination of tire wear markers in soil samples and their distribution in a roadside soil
N2 - Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0–2, 2–5, 5–10, and 10–20 cm. Four fine fractions, 1 000–500, 500–100, 100–50, and <50 μm, were analyzed.
TW contents based on SBR ranged from 155 to 15 898 mg kg−1. TW contents based on zinc were between 413 and 44 812 mg kg−1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance.
The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation.
KW - Microplastic
KW - TED-GC/MS
KW - Tire wear
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543344
DO - https://doi.org/10.1016/j.chemosphere.2022.133653
VL - 294
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-54334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Axel
T1 - Representative sampling of roadside soil and determination of tire wear contents by TED-GC/MS
N2 - The presentation describes microplastic findings from tyre wear near roads. Both the sampling and the analysis are presented.
T2 - Mikroplastik Workshop der Hochschule Zittau
CY - Online meeting
DA - 25.11.2021
KW - Mikroplastik
KW - Reifenabrieb
KW - TED-GC/MS
KW - Probennahme
PY - 2021
AN - OPUS4-53831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rösler, Alexander
A1 - Weidner, Steffen
A1 - Klamroth, Tillmann
A1 - Müller, Axel HE
A1 - Schlaad, Helmut
T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents
N2 - AbstractThe kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
KW - Myrcene
KW - Anionic polymerization
KW - MALDI TOF MS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649039
DO - https://doi.org/10.1002/pi.6772
SN - 0959-8103
SP - 1
EP - 8
PB - Wiley
AN - OPUS4-64903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lange, Axel
A1 - Kupsch, Andreas
A1 - Hentschel, Manfred P.
A1 - Müller, Bernd R.
T1 - Straightforward correction of X-ray detector backlighting
N2 - A novel approach to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background signals ('backlighting') of 2D X-ray detectors is suggested. Depending on the detector geometry the mechanism may be different, either based on the optical scattering of the fluorescent screen materials into optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert Beers law in single projections (radiographs) as function of the detector area coverage and the magnitude of the attenuation.
The absorption of multiple metal sheets is investigated by monochromatic synchrotron radiation, thus excluding beam hardening. The proposed correction procedure simply requires the individual subtraction of one and the same fraction of the primary and transmitted mean intensity, as a constant (non-local) scattering mechanism is assumed.
T2 - 18th WCNDT - World conference on nondestructive testing
CY - Durban, South Africa
DA - 16.04.2012
KW - X-ray detector backlighting
KW - Radiography
KW - Fluorescent screen
KW - Diffuse background
KW - Computed tomography
PY - 2012
UR - http://www.ndt.net/article/wcndt2012/papers/205_wcndtfinal00205.pdf
SN - 978-0-620-52872-6
SP - 1
EP - 8(?)
AN - OPUS4-25835
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lange, Axel
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Hentschel, Manfred P.
T1 - Edge artefacts of radiographic images by X-ray refraction
N2 - The relevance of nano sized structures and interfaces in upcoming technologies requires new non-destructive Xray techniques exploiting attenuation as well as scattering. In the course of driving the resolution and the contrast of modern radiography into micro and nano metre dimension the inevitable scattering effects require increased attention. Several radiologists interpret the observed edge artefacts simply by 'phase contrast' due to different X-ray path lengths within the sample and others refer to Fresnel scattering. The ultra small angle scattering is of high intensity and may reach the level of the primary beam. We present monochromatic synchrotron measurements on rather simply shaped objects (such as plates and cylinders) which prove clearly the dominance of refraction intensity over total reflection and coherent small angle scattering. The refraction conditions hold for angles of incidence of several degrees to the surface, but typical deflection angles range from several seconds to minutes of arc. Additionally to the concept of 'phase contrast' of the primary beam its deflection becomes the essential issue. The appropriate removal of the attenuation contribution enables the imaging of inner surfaces and interfaces by refraction scanning topography. The presented measurements of reference particles demonstrate the reliability of laboratory refraction scanners applying X-ray tubes.
T2 - 18th WCNDT - World conference on nondestructive testing
CY - Durban, South Africa
DA - 16.04.2012
KW - X-ray refraction
KW - Small angle scattering
KW - Phase contrast radiography
KW - Refraction topography
KW - Nanostructures
KW - Nanocracks
PY - 2012
UR - http://www.ndt.net/article/wcndt2012/papers/274_wcndtfinal00274.pdf
SN - 978-0-620-52872-6
SP - 1
EP - 11
AN - OPUS4-25836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
T1 - Numerical correction of X-ray detector backlighting
N2 - A novel approach to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background signals ('backlighting') of 2D X-ray detectors is suggested. Depending on the detector geometry the mechanism may be different, either based on the optical scattering by the fluorescent screen materials into optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert–Beer's law in single projections (radiographs). When used as input data for computed tomography these violations are directly observed via modulation of the projected mass as a function of the rotation phase and the samples aspect ratio (dynamics). The magnitude of the diffuse background signal depends on the detector area covered by the projected sample. They are more pronounced the smaller the shadowed area and the stronger the total attenuation. This implies that the reconstruction suffers from additional anisotropic artifacts caused by elongated sample structures. This issue is studied simply by absorption of flat plates in a conventional laboratory radiography set-up and at a synchrotron radiation facility. In the latter case beam hardening artifacts can be excluded due to the monochromatic radiation. The proposed correction procedure requires simple integral intensity offsets as a constant (non-local) light scattering mechanism is assumed.
KW - Detector backlighting
KW - X-ray detector scattering
KW - Fluorescent screen
KW - Diffuse background
KW - Computed tomography
PY - 2012
DO - https://doi.org/10.3139/146.110659
SN - 1862-5282
VL - 103
IS - 2
SP - 174
EP - 178
PB - Carl Hanser
CY - München
AN - OPUS4-25553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rösler, Alexander
A1 - Weidner, Steffen
A1 - Klamroth, Tillmann
A1 - Müller, Axel H. E.
A1 - Schlaad, Helmut
T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents
N2 - The kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations.
KW - MALDI-TOF MS
KW - Anionic polymerization
KW - β‐myrcene
KW - Kinetics
KW - Reaction order
KW - Activation energy
KW - Microstructure
KW - Quantum chemical calculations
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630900
DO - https://doi.org/10.1002/pi.6772
SN - 1097-0126
SP - 1
EP - 8
PB - Wiley
CY - New York, NY
AN - OPUS4-63090
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rösler, Alexander
A1 - Weidner, Steffen
A1 - Klamroth, Tillmann
A1 - Müller, Axel HE
A1 - Schlaad, Helmut
T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents
N2 - AbstractThe kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
KW - Myrcene
KW - Anionic polymerization
KW - Reaction order
KW - Activation energy
KW - Microstructure
KW - Quantum chemical calculation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636840
DO - https://doi.org/10.1002/pi.6772
SN - 0959-8103
SP - 1
EP - 8
PB - Wiley
AN - OPUS4-63684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -